Adds a reusable right-click / context menu Blazor component for the AdminUI:
- ContextMenu.razor: right-click surface (browser menu suppressed) + optional
ellipsis fallback trigger, both anchoring the menu at the pointer; keyboard
nav (arrows/Enter/Esc), transparent backdrop outside-click close (no JS).
- ContextMenu.razor.css: scoped styles on the shared theme tokens.
- ContextMenuItem.cs: Label/OnClick/Icon/Disabled/IsSeparator model + Separator().
- Dev demo page at /dev/context-menu-demo.
Claude-Session: https://claude.ai/code/session_01LVneM3eh1UtJxEisFXgmox
Joseph Doherty